As a measure for utilizing the characteristics of the oxytetramethylene structure such as weather resistance, low viscosity and the like, various attempts have been made to polymerize tetrahydrofuran by ring-opening to obtain a product having functional groups at the end portions thereof.
For example, a number of polyoxytetramethylene glycols having hydroxyl groups at both ends of polyoxytetramethylene chains and having various molecular weights have been prepared by the ring-opening polymerization of tetrahydrofuran and, marketed as raw materials for polyurethane resins. Also, Matveeva et al have reported in Inst. Chem. Phys. Moscow, 1974, 21(3), 191-3, tetramethylene glycol dimethacrylate having at both ends of the tetramethylene chain, polymerizable double bonds, which is useful as a crosslinking monomer, and P. Rempp et al have reported in Polymer Bull. 3, 83-89, 1980, a class of compounds having a considerable number of oxytetramethylene repeating units and a polymerizable vinyl group at only one end portion thereof.
In an acrylic resin to be used as a resinous vehicle in the paint industry, it is often required, from the standpoint of reaction with a hardener such as aminoplast resin, isocyanate compound and the like, and the reaction with a compound having a carboxyl, amino or epoxy group, to incorporate hydroxyl groups into said acrylic resin. The latter is known as a hardening type acrylic resin.
For this end, it is highly desired that a polymerizable vinyl group is located at one end of the oxytetramethylene chain and a hydroxyl group at the other end thereof. In U.S. Pat. No. 4,264,705, there is disclosure of a compound having oxytetramethylene repeating units and having both polymerizable double bond and hydroxyl group at the respective end portions. However, since the said oxytetramethylene unit number (n) is only 2, the desired characteristics such as low viscosity, high resilience and the like cannot be expected with the resulted resin even when used as a constituting material thereof.
It is, therefore, an object of the invention to provide a novel class of polymerizable monomers having a number of oxytetramethylene repeating units and having a polymerizable double bond at one end and hydroxyl group at the other end of the polyoxytetramethylene chain, which can be advantageously prepared in a higher reaction yield in an industrial scale of production and can be used as reactive monomer in the preparation of a novel vinyl resin having a flexible polyoxytetramethylene structure in it.
An additional object of the invention is to provide such vinyl resin composition which is highly reactive in crosslinking with a hardener, of comparatively lower viscosity nature, and capable of resulting in a highly resilient, tough, and flexible coating.